ACKERMANS/TENACITY has disgusting customer service

I am at my wits end with the Ackermans/Tenacity Group. They literally call me over 10x a day. I work from 6am to 6pm, and have told them this numerous times via email and on a call, yet they still keep calling me. It is disturbing my work as the phone keeps ringing. They call me every few MINUTES, not even hours. When I answered one time, the agent shouted at me to just say when I am going to pay. When I told him that I sent an email, he told me that he would keep calling me until I told him. That is disgusting behavior and I have taken this further and emailed Ackermans/Tenacity regarding this. The law states that you can not call someone more than 7 times a week. They call me at least 15 times a day.